1. Field of the Invention
The present invention relates generally to the drawing of fluid samples and more particularly to the drawing of multiple fluid samples through a hollow needle inserted into a human, other animal, or other fluid source.
2. Background Information
The invention presented in the present application is believed to solve, in a simple and effective fashion, a problem which has long plagued medical professionals: simultaneously drawing more than one sample of a fluid, particularly blood, in a manner which greatly reduces the chances of an accidental needle stick. For example, in many states a doctor or other medical professional is required to take two samples of blood from the every newborn baby. The samples may be taken by venipuncture of the newborn or, more commonly, from the umbilical cord. Cord samples may be taken by cord venipuncture or by letting cord blood escape or drip from the cord and collecting a sample of the blood. The later method involves risk of contamination from the various body fluids present during birth. Because diseases such as HIV and certain types of hepatitis may be transmitted by exchange of blood caused by accidental needle sticks, a method of taking such samples in a manner which reduces the chances of accidental needle stick is greatly desired.
Several attempts have been made to at least partially solve problems relating to drawing multiple samples of blood or other fluids with a single needle insertion.
One such attempt is disclosed in the patent to Bonn (U.S. Pat. No. 5,097,842, Mar. 24, 1992) which discloses a device for extracting blood, particularly blood from the umbilical cord, and obtaining two or more samples with a single needle insertion. The device includes a valve housing with a primary nipple in the front and two secondary nipples in the back. The nipples are all connected internally. A valve interposed between the primary and secondary nipples may be set to close the connection between the primary nipple and both secondary nipples or to open the connection between the primary nipple and either of the secondary nipples. Needles may be affixed to the primary nipple and to each of the secondary nipples. Evacuated tubes with stoppers may be forced onto the needles on the secondary nipples. The primary needle may be injected into a blood vessel such as in the umbilical cord and, by manipulation of the valve, blood samples taken into either or both of the evacuated tubes.
Another attempt to solve problems relating to drawing multiple fluid samples is disclosed in Golden (U.S. Pat. No. 4,676,256, Jun. 30, 1987) which discloses a hypodermic device which may be used to draw several samples of blood using one insertion needle and one insertion. The device includes an insertion needle which is attached to a manifold having a number of sockets containing an equal number of upright needles. The tops of the sockets are covered by plugs which may slide within the sockets. Capped vacuum tubes corresponding to the number of samples desired are pushed down into the sockets which causes the plugs to be pushed downward within the socket and the plugs and the caps of the vacuum tubes are pierced by the upright needles. A number of samples corresponding to the number of tubes used may then be collected at one time with one insertion.
The ideal multiple draw syringe provides a method of drawing multiple samples of a body fluid through an insertion needle with only one insertion in a manner which greatly reduces the chances of an accidental needle stick and provides for minimum manipulation of needles. The ideal multiple draw syringe should also be simple, lightweight, compact, easy to use, and inexpensive.